depends, i came from php4 and didn't really touch the level of OOP needed for the php5 kohana framework, i've used classes and functions but the HMVC is a process on it's own to learn, when it comes to Kohana vs YII i'd have to say kohana is easier to pickup.

my only dislike of Kohana is that the documentation is all over the place and outdated and it's not till you try it do you realize you were looking at the version before, ie : 3.0 vs 3.1 is different.. alot.. i'm still getting my head around it